1. Field of the Invention
The present invention relates to an image forming apparatus. More specifically, the present invention relates to an image forming apparatus such as a copying machine, printer, facsimile and etc., in which components such as a motor, light source and etc. for executing an image forming operation are controlled by a microcomputer.
2. Description of the Prior Art
In such a kind of image forming apparatus, if and when a specific signal indicative of a normal operation is not periodically outputted from a microcomputer to a supervising portion for some reason, the supervising portion continuously applies a reset signal to the microcomputer at intervals. Therefore, in a case where the image forming operation is started just after the microcomputer is reset, for example, the image forming operation is intermittently executed if the reset signal is repeatedly inputted to the microcomputer at short intervals.
In a case of a copying machine, for example, a scanning unit for exposing an original is moved to a home position when a power switch is turned-on, and when a start key is depressed, the scanning unit is started to move from the home position. However, in a case of a copying machine in which the scanning unit is moved to the home position just after the turning-on of the power switch, the scanning unit repeats the movement and the stop alternately if the supervising portion continuously outputs the reset signal at short intervals due to an abnormality of the microcomputer, and therefore, there is the possibility of a failure of the scanning unit.